Johns Manville Crawl Space Encapsulation Nationwide

Johns Manville Crawl Space Encapsulation: The Fort Worth Owner’s Guide

We stock and install Johns Manville crawl space encapsulation materials throughout Fort Worth, and most full encapsulation jobs run between $4,800 and $9,400 depending on square footage, access, and whether any existing vapor barrier needs to be torn out first. We can usually start within three to five business days, and emergency repairs on failed liner sections are often same-week. In our experience, Fort Worth homeowners discover they have an encapsulation problem one of three ways: a musty smell that creeps up through the floorboards, standing water or damp soil visible through a crawl space vent, or a floor that feels cold in January no matter how hard the furnace runs.

Call (817) 730-5474

Johns Manville vapor barriers and crawl space liners are tough materials, but Fort Worth’s clay-heavy soil and our wild swing between wet springs and bone-dry summers puts real strain on them. When a liner fails, it fails where the seams meet or where a pier pokes through, and that’s where we start looking.

Which Johns Manville Models This Applies To

Johns Manville’s crawl space encapsulation line runs two main product families: the JM Vapor Shield series, which includes reinforced poly liners in 10-mil, 12-mil, and 20-mil thicknesses, and the JM CrawlShield panels, which are rigid insulation boards with a built-in vapor barrier facing. If you have a white or silver reinforced liner with a printed JM logo, you’re almost certainly working with Vapor Shield. If you see foam board with a foil or white film face on the crawl space walls, that’s CrawlShield.

The compatibility gotcha we run into most often in Fort Worth: Vapor Shield’s 10-mil product was never designed for full encapsulation, only for basic ground cover over dirt. If a previous contractor installed 10-mil as the primary liner and taped the seams, it tends to tear at the tape lines within three to five years. The 12-mil and 20-mil are the real encapsulation products. We carry 12-mil Vapor Shield and both CrawlShield thicknesses on our trucks, and we can order 20-mil into Fort Worth within three days.

For OEM versus aftermarket: Johns Manville makes their own seam tape and accessories, but quality aftermarket butyl tape and mechanical fasteners work just as well at roughly 30 percent less. We use JM tape when the warranty on the existing liner is still active, and aftermarket when the liner is older and warranty replacement isn’t on the table anyway.

Signs Your Johns Manville Crawl Space Encapsulation Is Failing

• Damp, earthy smell in the living space. This means the liner has torn somewhere and moisture is migrating up from exposed soil. In Fort Worth, this is most common in spring when the clay soil is saturated and hydrostatic pressure pushes vapor up hard against the liner.
• Condensation on crawl space walls or on the underside of floor joists. The barrier on the walls has delaminated or pulled away from its fasteners, letting warm outside air hit cooler surfaces and sweat. We see this a lot in homes around TCU with older pier-and-beam foundations where moisture levels shift week to week.
• Liner pooled with water or visibly sagging between piers. Water is either entering from outside (a gutter issue or grade problem) or the liner’s seams have opened and groundwater is wicking up. Standing water on top of a liner is usually a drainage problem, not a liner failure, and it needs a different fix than replacing the barrier itself.
• Mold on the bottom of floor joists or on insulation batts in the floor cavity. This is the failure indicator that gets the most urgent calls. Once mold is present, the encapsulation has lost its seal, and the fix is repair the liner, address the moisture source, and replace the contaminated insulation.
• Ripped or brittle liner visible near crawl space entry points. Ultraviolet light from a seldom-used crawl space door degrades polyethylene over time. We often find the liner torn within five feet of the access hatch while the rest is serviceable.

Replacement Cost & What’s Included

For Fort Worth homes, a full Johns Manville Vapor Shield encapsulation starts around $4,800 for a small crawl space (800 to 1,000 square feet) with decent access, and runs up to $9,400 for larger spaces with low clearance, multiple piers, and significant prep work like removing failed liner and re-grading low spots. CrawlShield wall panels add $1,800 to $2,600 on average because they involve cutting, fitting, and mechanically fastening insulation board around plumbing, ductwork, and piers.

Here’s what the number includes, every time:

• Removal and disposal of failed liner if present
• Site prep: leveling high spots, filling low spots, covering sharp debris
• JM Vapor Shield 12-mil liner, seam-taped and mechanically fastened
• Full perimeter seal to foundation walls
• Pier wraps and seam detailing around columns
• Written price before work starts, with no change orders unless you approve them
• 365-Day Done Right Promise in writing

Parts versus labor: materials typically make up 35 to 40 percent of the total. The rest is prep, installation time, and disposal. We don’t break out a separate “parts warranty” because the 365-Day Done Right Promise covers the whole installation, parts and labor, for a full year. If a seam opens or a fastener pulls loose in that window, we’re back out at no charge.

DIY or Call Us?

You can absolutely do some prep work yourself: clearing debris from the crawl space access, trimming back shrubs so we can get materials in, and checking your gutters to make sure they’re not dumping water against the foundation. Those three things save real hours on install day. What you shouldn’t DIY is the liner itself. Crawl spaces in Fort Worth are notoriously tight, often 18 to 24 inches of clearance, and the work involves a lot of awkward crawling, cutting around plumbing, and sealing seams in low light. A missed seam or a poorly fastened liner edge quietly undoes the whole job and you won’t know until the smell comes back.

If your liner has a tear and you’re weighing options, call us at (817) 730-5474. Chase can come out, crawl the space himself, and tell you honestly whether you need a section repair or a full replacement. Estimates are free, and you’ll have a written number before any work starts.

FAQs

Get a Straight Answer on Your Crawl Space

If your crawl space smells off, your floors feel cold, or you’ve already found a tear in your liner, call (817) 730-5474. We’ll walk you through what we’re likely seeing based on what you describe, schedule a crawl space assessment, and put a written price in your hand before anything starts. That’s the Relay Visibility Guarantee, and it’s how we’ve done every job since 2003. Good insulation shouldn’t be a mystery, let me just show you the numbers. Laurel Attic Insulation Fort Worth is an independent service provider, not affiliated with Johns Manville, and we match the material to the job, not to whatever is on the truck.

Written by Chase Whitaker, Owner, Laurel Attic Insulation Fort Worth at Laurel Attic Insulation Fort Worth, serving Fort Worth and nearby areas.